Research on Adaptive Modulation Algorithm of Multimode Fiber Communication System Using Coherent Optical OFDM

Abstract

Coherent Optical OFDM (CO-OFDM) technology can take full advantage of the high frequency band-pass regions of the multimode fiber, and carry high-speed and high capacity communication. However, the deep fading in high frequency band pass region of the multimode fiber will affect the system performance. Adaptive Modulation Algorithm was studied. The authors proposed an algorithm using threshold allocation of optical signal to noise ratio (OSNR), and introduced the CO-OFDM multimode fiber communication systems based on adaptive modulation (AM).The experimental results show that AM-CO-OFDM multimode fiber communication systems reduces 2dB OSNR requirement than that without AM technology in 21.4Gb/s CO-OFDM signal transmission over 200km of multimode fiber.

Impact of the frequency response fluctuations of the multimode fiber on the OFDM transmission

“…The transmission of an adaptively modulated OFDM signal over multimode fiber has recently gained very high interest as well [1, 2]. As it comes for multimode fibers, numbers of concepts vary from baseband OFDM [1] to subcarrier OFDM generation [3], coherent [4, 5] and non‐coherent detection (Intensity Modulation—Direct Detection) [1, 2]. Most of the papers focus on some different modifications of an OFDM itself [3, 6, 7] and/or analysis of the impact of different impulse/frequency response of different multimode fiber samples on the transmission performance [8].…”